The show focuses around roommates Leonard and Sheldon, two highly intelligent scientists who attempt to expand their horizons upon the arrival of their new and extremely hot next door neighbor, Penny. Leonard instantly falls in love with Penny, but its clear Penny's not really looking for the nerdy type. Sheldon's not too enamored with their new neighbor since he's mainly stuck on himself, although Leonard's infatuation with Penny manages to make living with Leonard a little unnerving at times. Throw in two more nerdy scientists (friends Raj and Howard), one who is unable to speak when around women, and the other a geeky Jewish engineer who thinks he's God's gift to women, and The Big Bang Theory manages to be a big bang hit!
Raj's parent's setup him up on a date with a girl he grew up with in India, he's not too excited about being setup, plus he can't talk to women. But he soon discovers all it takes is for him to be drunk and he can't shut up! This causes him to be rather annoying on his date, leading Sheldon to step in and steal his date!
Leonard makes up an excuse to get out of going to Penny's performance of the play Rent because she's such a terrible singer, but Sheldon is not comfortable with what he thinks is a flimsy lie that Penny should easily be able to figure out. Therefore Sheldon weaves a lie so complex and intricate that it ends up growing out of control.
Sheldon's extremely beautiful twin sister is in town and all the guys try to gain her affection, but it's quickly halted when Sheldon proclaims he'll be the one who decides who dates her.
The gang decides to compete in the Physics Bowl, but quickly kicks out Sheldon when he begins to take control of the team. Out of spite Sheldon decides to start his own team to prove he's smarter than all of them.
Leonard bids on what he believes is a miniature model of the 1960's film The Time Machine prop, but when it's delivered, he discovers it's the actual time machine! In an attempt to move the time machine upstairs, Penny misses work and yells at Leonard for being so immature, this causes Leonard to decide to give up his science fiction collectibles.